Chicago Police investigate an officer-involved shooting in the North Austin neighborhood on the city's West Side late Sunday, September 9, 2012. / Brett T. Roseman for USA TODAY

by William Spain, Special for USA TODAY

by William Spain, Special for USA TODAY

CHICAGO - If the grimly regular tally of shootings provides plenty of grist for both the local and national media mills, the reality of violence in Chicago may be quite different - at least according to a study about to be released.

Crime in the city of Al Capone and John Gacy has dipped to a 40-year low, said Andrew Papachristos, a criminologist and associate professor at Yale University who conducted the research. Chicago officials aren't missing their chance to seize on the data and tout the improvement.

This year alone, "Chicago appears to be on track to have both the lowest violent crime rate since 1972, and lowest homicide rate since 1967," he said.

The report, titled 48 Years of Crime in Chicago, examines the crime trends in the city. Papachristos noted that while Chicago has long been thought of a bastion for criminals, it in fact ranks 19th in violent crime rates among large cities, on par with Houston and Minneapolis and below places like Detroit and St. Louis.

Even in New Haven, where Yale is located, "the rate is higher than Chicago," he added.

The Chicago Police Department reports that there were 483 murders in 2012, a number that has dropped to 392 so far this year. Overall crime is down 16%.

City leaders say the study as proof both that Chicago's gruesome reputation is undeserved and that recent stepped-up law enforcement and social services efforts are working.

"We have more work to do," Mayor Rahm Emanuel told USA TODAY. But "it does show that the things we are trying . . . are having an impact."

The crime dips have been uneven, with some more affluent areas - the largest beneficiaries of recent development - seeing the biggest fall-offs. But the overall trend has generally been citywide.

"More and more mothers, more and more neighborhoods can now enjoy a sense of normalcy," Emanuel said.

Emanuel is pushing what he calls the "Four Ps": policing, prevention, parenting and penalties.

Police Superintendent Garry McCarthy said that while Chicago has the fourth highest level of police per capita of the largest cities in the USA - behind Washington, D.C., Baltimore and Newark - law enforcement is just part of the solution.

"We are backing (policing) with social programs and things that will have a longer-term effect," he said. "We are not just trying to put a Band-aid on the problem."

The numbers, however, are of little comfort to some of those who live in Chicago's tougher regions.

"I have a neighbor who has been robbed twice in the last two years and she has a Rottweiler," said Donna Johnson, whose family has lived in the Roseland neighborhood on the city's Far South Side for 44 years. "As kids in the 1960s and 1970s, we felt very safe running around. As adults, we don't even walk to the store after dark."

Johnson said she has seen "no meaningful improvement" in the last few years: "A police car just drove past my house but that doesn't mean anything."

Still, crime rates have generally been dropping across the USA, a trend that resists explanation by criminologists and others, including Yale's Papachristos.

"I don't think it is any one thing," he said. "And it is certainly not tied to economics since crime is going down even as we have a crummy economy. It really has criminologists baffled."

In 2011, there were 2,128 shootings in the city, according to police figures. That number spiked to 2,364 in 2012 but was at 1,756 as of December 8 this year. The overall number of major crimes in the same period of 2011 was 80,527. That slipped to 74,078 in 2012 and to 62,392 to date in 2013.

Papachristos said that the data from 2013 "indicates that the index crime rate will continue to fall, with early estimates suggesting a rate of 4,251 per 100,000, a rate not seen since 1972."